Passively activated safety needle

Abstract

A passively activated safety needle assembly includes a needle assembly, a shield assembly and a safety cap. The needle assembly includes a hub and a needle cannula that projects from the hub. The shield assembly includes a safety shield that is mounting for sliding movement along the needle cannula. The shield assembly also includes a plurality of arms articulated to one another to permit sliding movement of the safety shield along the needle cannula from a proximal position to a distal position where the tip of the needle cannula is shielded. A spring is mounted to the shield assembly and is operative to drive the safety shield from its proximal position to its distal position. The safety cap is mounted over shield assembly and holds the shield assembly in the proximal position. The arms are held during usage of the safety needle. Upon release of the arms, the spring automatically drives the shield distally without any user activation.

What is claimed is:  
     
       1. A passively activated safety needle assembly comprising: 
       a needle cannula with opposite proximal and distal ends; and  
       a shield assembly having a safety shield slidably mounted on said needle cannula and movable from a proximal position substantially adjacent said proximal end of said needle cannula to a distal position surrounding said distal end of said needle cannula, said shield assembly further comprising a plurality of hingedly connected arms with at least two arms being hingedly connected at a hinge connection extending between said safety shield and a location in proximity to said proximal end of said needle cannula for limiting distal movement of said safety shield along said needle cannula, said shield assembly further comprising a torsion spring securably disposed at said hinge connection for urging said safety shield from said proximal position to said distal position.  
     
     
       2. The passively activated safety needle assembly of  claim 1 , further comprising a safety cap frictionally mounted over said needle cannula ond over portions of said shield assembly for holding said safety shield in said proximal position. 
     
     
       3. The passively activated safety needle assembly of  claim 1 , further comprising a needle hub secured to said proximal end of said needle cannula, and wherein said plurality of arms comprises a distal arm articulated to said safety shield and a proximal arm articulated in proximity to said hub, said proximal and distal arms being hingedly connected to one another at said hinge connection. 
     
     
       4. The passively activated safety needle assembly of  claim 3 , wherein said torsion spring is disposed between said hub and said proximal arm, said torsion spring urging said proximal arm about said articulation to said base for expanding said proximal and distal arms relative to one another and propelling said safety shield distally along said needle cannula. 
     
     
       5. The passively activated safety needle assembly of  claim 4 , wherein the base further comprises a thumb grip projecting from said base at a location opposite said proximal arm. 
     
     
       6. The passively activated safety needle assembly of  claim 3 , wherein said torsion spring is mounted at said hinged connection between said proximal and distal arms for urging said proximal and distal arms into an expanded condition and thereby driving said safety shield distally along said needle cannula. 
     
     
       7. The passively activated safety needle assembly of  claim 3 , wherein said shield assembly further comprises a base securely mounted to said needle hub, said proximal arm being articulated to said base. 
     
     
       8. The passively activated safety needle assembly of  claim 3 , wherein said safety cap includes a notch for slidably receiving said arms and holding said arms in a collapsed condition. 
     
     
       9. The passively activated safety needle assembly of  claim 3 , wherein said safety shield is unitary with said distal arm. 
     
     
       10. The passively activated safety needle assembly of  claim 3 , wherein said proximal arm is unitary with said base. 
     
     
       11. A passively activated safety needle assembly comprising: 
       a needle assembly having a needle cannula with opposite proximal and distal ends, a needle hub securely mounted to said proximal end of said needle cannula and being configured for mounting to a medical implement;  
       a shield assembly having a safety shield slidably mounted on said needle cannula and movable from a proximal position adjacent said hub to a distal position surrounding said distal end of said needle cannula, said shield assembly further comprising a distal arm hingedly connected to said safety shield, a proximal arm hingedly connected to said distal arm at a hinge and a base hingedly connected to said proximal arm, said base being securely mounted to said hub of said needle assembly, said shield assembly further comprising a torsion spring secured to said hinge and mounted to at least one of said arms for moving said arms in a direction for urging said safety shield to said distal position; and  
       a safety cap releasably engaged over said needle cannula and over portions of said shield assembly for holding said shield assembly in said proximal position.